A piezoelectric stick-slip rotary motion platform

Abstract

The present invention discloses a piezoelectric stick-slip rotational motion platform, comprising a base and a moving platform disposed above the base, an annular body disposed below the moving platform, and a first drive unit, a second drive unit, a third drive unit, and a fourth drive unit distributed equally on the outer circumference of the annular body in sequence; the first drive unit, the second drive unit, the third drive unit, and the fourth drive unit have the same structure, comprising a limiter, a flexible mechanism, and a piezoelectric actuator supported within the flexible mechanism, the piezoelectric actuator being disposed in the tangential direction of the outer arc surface of the annular body; the flexible mechanism comprising an inclined wedge block that presses against the extended end of the piezoelectric actuator; the inclined wedge block comprising a flat portion attached to the outer circumference of the annular body and an inclined portion facing away from the annular body, the limiter being disposed on the inclined portion. The moving platform, annular body, base stator, and four drive units of the present invention are simple to assemble and adjust, have a fast motion speed, a strong load capacity, and low friction and wear between the stator and the mover.

Description

Technical Field

[0001] The present invention belongs to the field of nanopositioning technology, and relates to a small-volume precision displacement driver with millimeter-level large stroke and nanometer-level high resolution, and in particular to a piezoelectric stick-slip positioning platform capable of generating rotational motion. Background Art

[0002] A piezoelectric stick-slip platform is a precision displacement actuator capable of achieving both millimeter- and even centimeter-scale travel and nanometer-scale high resolution. Under the action of a sawtooth voltage, the piezoelectric stick-slip rotary platform slowly extends and rapidly contracts the piezoelectric actuator, creating a static and dynamic friction difference between the stator and mover. This cumulatively adds the piezoelectric actuator's nanometer-scale linear displacement to the mover's continuous rotational displacement, thereby achieving a large rotation angle exceeding 360°. Compared to electromagnetic platforms, piezoelectric stick-slip platforms offer advantages such as the absence of a magnetic field, ease of control, and the absence of end effects and thrust fluctuations. Compared to ultrasonic resonant and inchworm-driven piezoelectric platforms, piezoelectric stick-slip platforms offer minimal wear, a simple control system, and fast stepping speeds. Therefore, piezoelectric stick-slip platforms offer unique advantages in micro- and nano-manipulation technologies requiring miniaturization, lightweight construction, and the absence of magnetic fields, such as microelectromechanical systems (MEMS) assembly, cell micromanipulation, and scanning electron microscopy (EM) observation. However, current piezoelectric stick-slip rotary platforms still have the following shortcomings:

[0003] 1) The overall structure of the motor is complex and not compact;

[0004] 2) The assembly and adjustment process of the stator and mover is complicated;

[0005] 3) The platform has a large retraction displacement per step and a slow movement speed;

[0006] 4) Insufficient driving force of the platform and low load capacity;

[0007] 5) Most platform guide mechanisms do not use guide rails as standard parts. On the one hand, this increases the processing and manufacturing costs. On the other hand, there is severe friction and wear between the stator and the mover, which reduces the life of the platform. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a piezoelectric stick-slip rotary motion platform with a reasonable structural layout, simple assembly and adjustment of the mover and stator, fast movement speed, strong load capacity, and low friction and wear between the stator and mover in response to the current status of the above-mentioned existing technology.

[0009] The technical solution adopted by the present invention to solve the above technical problems is as follows: a piezoelectric stick-slip rotational motion platform includes a base and a moving platform arranged above the base, an annular body is provided below the moving platform, and a first drive unit, a second drive unit, a third drive unit, and a fourth drive unit are distributed in equal parts in sequence on the outer circumference of the annular body;

[0010] The first drive unit, the second drive unit, the third drive unit, and the fourth drive unit have the same structure, including a limiter, a flexible mechanism, and a piezoelectric actuator supported in the flexible mechanism, the piezoelectric actuator being arranged in a tangential direction of the outer arc surface of the annular body; the flexible mechanism includes an inclined wedge block pressed against the extended end of the piezoelectric actuator;

[0011] The inclined wedge block includes a flat surface attached to the outer peripheral surface of the annular body and an inclined surface away from the annular body, and the limiter is mounted on the inclined surface. The moving platform and the annular body are the movers, and the base and the four drive units are the stators.

[0012] To optimize the above technical solutions, the following measures are also taken:

[0013] A fixing ring is coaxially provided on the inner side of the annular body, and the fixing ring is fixed to the base; and first balls are evenly arranged between the fixing ring and the annular body.

[0014] In a preferred solution, the annular body and the fixed ring are respectively provided with guide grooves for the first balls to roll.

[0015] In a preferred embodiment, the flexible mechanism also includes a fixed part, a rectangular flexible hinge, a rigid part and an arc-shaped flexible hinge connected in sequence. There is a pair of arc-shaped flexible hinges, which are arranged on both sides of the piezoelectric actuator and connected to the inclined wedge block; a gasket is sandwiched between the rigid part and the fixed end of the piezoelectric actuator, and the fixed part is fixed to the base by fastening screws.

[0016] In a preferred solution, the limiting member is an elastic ball head pre-tightening screw, the base is provided with a boss, and the boss is provided with a first screw hole for the limiting member to be screwed into.

[0017] In a preferred embodiment, the bending direction of the arc-shaped flexible hinge is parallel to the central axis of the annular body.

[0018] In a preferred solution, the rigid part is provided with a second screw hole leading to the piezoelectric actuator, and the second screw hole is provided with a pre-tightening adjustment screw pressing against the end of the piezoelectric actuator; the fixing part is provided with a first operating hole leading to the second screw hole.

[0019] In a preferred solution, the base is provided with an accommodating cavity with an opening facing the moving platform, and the first driving unit, the second driving unit, the third driving unit and the fourth driving unit, the boss and the limiting member are all located in the accommodating cavity.

[0020] In the preferred embodiment, the base is laterally provided with a second operating hole leading from the outside to the first operating hole, which is convenient for a screwdriver to reach in and adjust the preload adjustment screw; the base is laterally provided with a third operating hole leading from the outside to the limit member, which is convenient for a screwdriver to reach in and adjust the limit member.

[0021] In order to prevent the inclined wedge from shaking up and down during operation, a guide groove is provided on the inclined portion for the limiting piece to roll and slide.

[0022] Compared with the prior art, the piezoelectric stick-slip rotational motion platform of the present invention includes a base and a moving platform arranged above the base, an annular body is provided below the moving platform, and the outer circumference of the annular body is equally distributed with a first drive unit, a second drive unit, a third drive unit and a fourth drive unit; the first drive unit, the second drive unit, the third drive unit and the fourth drive unit have the same structure, including a limiter, a flexible mechanism, and a piezoelectric actuator supported in the flexible mechanism, and the piezoelectric actuator is arranged in the tangential direction of the outer arc surface of the annular body; the flexible mechanism includes an inclined wedge block that presses on the extended end of the piezoelectric actuator; the inclined wedge block includes a flat portion attached to the outer circumference of the annular body, and an inclined portion facing away from the annular body, and the limiter is placed on the inclined portion.

[0023] Slowly apply voltage (t 10 to t 11 ), the extended piezoelectric actuator pushes the annular body to realize rotational motion, and then pushes the dynamic platform to realize rotational motion. During the extension process of the piezoelectric actuator, the static friction between the annular body and the inclined wedge block increases continuously under the action of the inclined wedge block; after a certain angle of phase difference, at t 20 Slowly apply voltage to the piezoelectric actuators of the second and fourth drive units (t 20 to t 21 ), the extended piezoelectric actuator also pushes the annular body to realize rotational motion. When the piezoelectric actuators of the first drive unit and the third drive unit reach the rated voltage (t 11 ), the piezoelectric actuators of the first and third drive units are suddenly powered off, and the first and third drive units quickly recover. At this time, the moving platform and the annular body are still rotating under the push of the second and fourth drive units, thereby increasing the movement speed and driving force. After the first and third drive units complete a cycle of movement, the next movement cycle (t 12 to t 13 ), the second drive unit and the fourth drive unit are also at t 22 The next movement cycle begins, and the cycle repeats, continuously pushing the moving platform to rotate, thereby achieving a large rotation angle exceeding 360 degrees. The mover and stator of the present invention are simple to assemble and adjust, have a fast movement speed, a strong load capacity, and low friction and wear between the stator and the mover. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is a schematic diagram of the three-dimensional structure of the first embodiment of the present invention;

[0025] Figure 2 yes Figure 1 Schematic diagram of the decomposition;

[0026] Figure 3 yes Figure 2 Further decomposition of the schematic;

[0027] Figure 4 is a structural diagram of a first driving unit according to a first embodiment of the present invention;

[0028] Figure 5 yes Figure 4 It is a decomposition diagram;

[0029] Figure 6 This is a top view of the present invention after removing the moving platform;

[0030] Figure 7 is a structural diagram of the first driving unit in Example 2;

[0031] Figure 8 This is the working timing diagram of the piezoelectric stick-slip rotary motion platform. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0033] Figures 1 to 7 It is a structural schematic diagram of the present invention.

[0034] The figures are marked as follows: first drive unit 1, second drive unit 2, third drive unit 3, fourth drive unit 4, moving platform 5, base 6, boss 61, first screw hole 611, third operating hole 62, second operating hole 63, accommodating chamber 64, annular body 71, first ball 72, fixing ring 73, guide groove 74, flexible mechanism 80, inclined wedge block 81, flat portion 811, inclined portion 812, guide groove 813, arc-shaped flexible hinge 82, rigid portion 83, second screw hole 831, rectangular flexible hinge 84, fixing portion 85, first operating hole 851, limiter 91, fastening screw 92, preload adjustment screw 93, piezoelectric actuator 10, gasket 11.

[0035] Example 1, as Figures 1 to 6 As shown, a piezoelectric stick-slip rotational motion platform includes a base 6 and a movable platform 5 disposed above the base 6. An annular body 71 is disposed below the movable platform 5. A first drive unit 1, a second drive unit 2, a third drive unit 3, and a fourth drive unit 4 are equally distributed on the outer circumference of the annular body 71.

[0036] The first drive unit 1, the second drive unit 2, the third drive unit 3, and the fourth drive unit 4 have the same structure, including a stopper 91, a flexible mechanism 80, and a piezoelectric actuator 10 supported within the flexible mechanism 80. The piezoelectric actuator 10 is disposed in a tangential direction of the outer arc surface of the annular body 71. The flexible mechanism 80 includes an inclined wedge 81 that presses against the extended end of the piezoelectric actuator 10.

[0037] The inclined wedge 81 includes a flat portion 811 attached to the outer circumference of the annular body 71 and an inclined portion 812 facing away from the annular body 71. The stopper 91 is mounted on the inclined portion 812. The movable platform 5 and the annular body 71 are movers, and the base 6 and the four drive units are stators.

[0038] In the embodiment, Figure 2 、 3 As shown in FIG6 , a fixing ring 73 is coaxially provided on the inner side of the annular body 71 and fixed to the base 6 ; first balls 72 are evenly arranged between the fixing ring 73 and the annular body 71 . The annular body 71 can coaxially rotate around the fixing ring 73 , thereby increasing the stability of the moving platform 5 .

[0039] In the embodiment, Figure 3 As shown, the annular body 71 and the fixing ring 73 are respectively provided with a guide groove 74 for the first ball 72 to roll. The annular body 71, the first ball 72 and the fixing ring 73 can also be replaced by bearings. In the preferred embodiment, there is a gap between the lower end of the annular body 71 and the base 6.

[0040] In the embodiment, Figure 4 and Figure 5 As shown, the flexible mechanism 80 further includes a fixed portion 85, a rectangular flexible hinge 84, a rigid portion 83, and an arc-shaped flexible hinge 82 connected in sequence. There is a pair of arc-shaped flexible hinges 82, which are respectively provided on both sides of the piezoelectric actuator 10 and connected to the inclined wedge block 81; a gasket 11 is sandwiched between the rigid portion 83 and the fixed end of the piezoelectric actuator 10, as shown in FIG. Figure 2 and Figure 3 As shown, the fixing portion 85 is fixed to the base 6 by fastening screws 92 .

[0041] In the embodiment, the limiting member 91 is an elastic ball head pre-tightening screw, such as Figure 3 As shown, the base 6 is provided with a boss 61 , and the boss 61 is provided with a first screw hole 611 for the limiting member 91 to be screwed into.

[0042] In the embodiment, Figure 3 As shown, the bending direction of the arc-shaped flexible hinge 82 is parallel to the central axis of the annular body 71, that is, the arc-shaped flexible hinge 82 bends and moves along the up-down direction.

[0043] In the embodiment, Figures 2 to 5 As shown, the rigid portion 83 is provided with a second screw hole 831 leading to the piezoelectric actuator 10 , and the second screw hole 831 is provided with a preload adjustment screw 93 that presses against the end of the piezoelectric actuator 10 ; the fixing portion 85 is provided with a first operating hole 851 leading to the second screw hole 831 .

[0044] In the embodiment, Figure 2 、 3As shown, the base 6 is provided with an accommodating cavity 64 opening toward the moving platform 5 , and the first driving unit 1 , the second driving unit 2 , the third driving unit 3 , the fourth driving unit 4 , the boss 61 and the limiting member 91 are all located in the accommodating cavity 64 .

[0045] In the embodiment, Figure 2 、 3 As shown, the base 6 is laterally provided with a second operating hole 63 leading from the outside to the first operating hole 851, which is convenient for a screwdriver to reach in and adjust the preload adjustment screw 93; the base 6 is laterally provided with a third operating hole 62 leading from the outside to the limit member 91, which is convenient for a screwdriver to reach in and adjust the limit member 91.

[0046] Embodiment 2: The structure of embodiment 2 is similar to that of embodiment 1, except that a guide groove 813 is provided on the inclined portion 812 for the limiting member 91 to slide, thereby preventing the inclined wedge block 81 from shaking up and down during operation.

[0047] In the embodiment, the guide groove 813 extends through the planar portion 811 and the inclined portion 812 and is filled with rubber, the end surfaces of which are flush with the planar portion 811 and the inclined portion 812. When the stopper 91 presses against the rubber in the guide groove 813, the guide groove 813 slightly overflows from the planar portion 811, thereby increasing the static friction between the planar portion 811 and the annular body 71.

[0048] Working principles of Example 1 and Example 2:

[0049] like Figure 8 As shown, voltage (t 10 to t 11 ), the extended piezoelectric actuator 10 pushes the annular body 71 to realize rotational motion, and then pushes the movable platform 5 to realize rotational motion. During the extension process of the piezoelectric actuator 10, the static friction between the annular body 71 and the inclined wedge block 81 continuously increases under the action of the inclined wedge block 81; after a certain angle of phase difference, at t 20 A voltage (t 20 to t 21 ), the extended piezoelectric actuator 10 also pushes the annular body 71 to realize the rotational motion. When the piezoelectric actuators 10 of the first driving unit 1 and the third driving unit 3 reach the rated voltage (t 11), the piezoelectric actuators 10 of the first drive unit 1 and the third drive unit 3 are suddenly powered off, and the first drive unit 1 and the third drive unit 3 quickly recover. At this time, the moving platform 5 and the annular body 71 are still rotating under the impetus of the second drive unit 2 and the fourth drive unit 4, thereby increasing the movement speed and driving force. After the first drive unit 1 and the third drive unit 3 complete a cycle of movement, the next movement cycle (t 12 to t 13 ), the second drive unit 2 and the fourth drive unit 4 are also at t 22 The next movement cycle begins, and the cycle repeats itself, continuously pushing the moving platform 5 to rotate, thereby achieving a large rotation angle of more than 360°.

[0050] The best embodiment of the present invention has been described, and various changes or modifications can be made by those skilled in the art without departing from the scope of the present invention.

Claims

1. A piezoelectric stick-slip rotational motion platform, comprising a base (6) and a moving platform (5) arranged above the base (6), characterized in that: An annular body (71) is provided below the moving platform (5), and a first drive unit (1), a second drive unit (2), a third drive unit (3) and a fourth drive unit (4) are equally distributed on the outer circumference of the annular body (71); The first drive unit (1), the second drive unit (2), the third drive unit (3) and the fourth drive unit (4) have the same structure, comprising a limiter (91), a flexible mechanism (80), and a piezoelectric actuator (10) supported in the flexible mechanism (80), wherein the piezoelectric actuator (10) is arranged in a tangential direction of the outer arc surface of the annular body (71); the flexible mechanism (80) comprises an inclined wedge block (81) pressed against the extended end of the piezoelectric actuator (10); The inclined wedge block (81) includes a flat surface portion (811) attached to the outer peripheral surface of the annular body (71) and an inclined surface portion (812) away from the annular body (71), and the limiting member (91) is mounted on the inclined surface portion (812); A fixing ring (73) is coaxially provided on the inner side of the annular body (71), and the fixing ring (73) is fixed to the base (6); a first ball (72) is evenly arranged between the fixing ring (73) and the annular body (71); The annular body (71) and the fixing ring (73) are respectively provided with a guide groove (74) for the first ball (72) to roll; The flexible mechanism (80) further includes a fixed portion (85), a rectangular flexible hinge (84), a rigid portion (83) and an arc-shaped flexible hinge (82) connected in sequence. The arc-shaped flexible hinge (82) comprises a pair of hinges, which are arranged on both sides of the piezoelectric actuator (10) and connected to the inclined wedge block (81). A gasket (11) is sandwiched between the rigid portion (83) and the fixed end of the piezoelectric actuator (10). The fixed portion (85) is fixed to the base (6) by a fastening screw (92).

2. The piezoelectric stick-slip rotational motion platform according to claim 1, characterized in that: The limiting member (91) is an elastic ball head pre-tightening screw, the base (6) is provided with a boss (61), and the boss (61) is provided with a first screw hole (611) for the limiting member (91) to be screwed in.

3. The piezoelectric stick-slip rotational motion platform according to claim 2, characterized in that: The bending direction of the arc-shaped flexible hinge (82) is parallel to the central axis of the annular body (71).

4. The piezoelectric stick-slip rotational motion platform according to claim 3, characterized in that: The rigid portion (83) is provided with a second screw hole (831) leading to the piezoelectric actuator (10), and the second screw hole (831) is provided with a pre-tightening adjustment screw (93) that presses against the end of the piezoelectric actuator (10); the fixing portion (85) is provided with a first operating hole (851) leading to the second screw hole (831).

5. The piezoelectric stick-slip rotational motion platform according to claim 4, characterized in that: The base (6) is provided with a receiving cavity (64) opening toward the moving platform (5); the first drive unit (1), the second drive unit (2), the third drive unit (3), the fourth drive unit (4), the boss (61) and the limiting member (91) are all located in the receiving cavity (64).

6. The piezoelectric stick-slip rotational motion platform according to claim 5, characterized in that: The base (6) is laterally provided with a second operating hole (63) leading from the outside to the first operating hole (851), so as to facilitate a screwdriver to penetrate and adjust the preload adjustment screw (93); the base (6) is laterally provided with a third operating hole (62) leading from the outside to the limiter (91), so as to facilitate a screwdriver to penetrate and adjust the limiter (91).

7. The piezoelectric stick-slip rotational motion platform according to claim 6, characterized in that: The inclined wedge block (81) is provided with a guide groove (813) on the inclined portion (812) for the limiting member (91) to slide.

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